I can confirm the ground clearance of the CX-3 is 155mm which is a tad over 6 inches (6.1 would be right). This is the same as a Mazda3 by the way. The HR-V is 170mm which is a bit under 7 inches (6.7 would be spot on).
This lower center of gravity than other cars in this segment no doubt contributes to the sharp responses noted in the tests. I certainly would be more comfortable with an inch more clearance to get through at least the snow in these northern climes
I think the clearance is sufficient for this class. Good for wet weather and slush. I'm really pleased with the other dimensions. Same height as my x1 which is perfect (for me). It's also lightest and has the tightest turning radius in the bunch. Could use a larger fuel tank tho. 11.8 is Mazda2-sized. Wish it had the 13.2 from the 3.
Before I became aware of the release of CX3, I was choosing between Subaru Crosstrec and CX 5. Crosstrec is basically a gussied up Imprezza lifted 2 inches. Each of these vehicles has their strengths and weaknesses, including those which are purely subjective. The comfort level of taking the vehicle off the paved road is an important one. In this consideration, 6. 1 inches is really to limiting for me.
The Buick Encore and Chevrolet Trax are only 6.2 inches. I had a Pontiac Vibe with 6.2 inches and agreed that I would like higher in a CUV/SUV. But I ended up buying a Mazda 3 which is also 6.1 inches. I figured that better fuel economy and cargo room at the same ground clearance of the 3 over the CX-3 made more sense.